Field of the Disclosure
The present disclosure generally relate to controlling lost circulation in a wellbore during drilling with a drilling fluid. More specifically, embodiments of the disclosure relate to an organic, particulate lost circulation material.
Description of the Related Art
Lost circulation is one of the frequent challenges encountered during drilling operations. Lost circulation, which can be encountered during any stage of operations, occurs when drilling fluid (or drilling mud) pumped into a well returns partially or does not return to the surface. While some fluid loss is expected, fluid loss beyond acceptable norms is not desirable from a technical, an economical, or an environmental point of view. About 75% of the wells drilled per year encounter lost circulation problems to some extent. Lost circulation is associated with problems with well control, borehole instability, pipe sticking, unsuccessful production tests, poor hydrocarbon production after well completion, and formation damage due to plugging of pores and pore throats by mud particles. In extreme cases, lost circulation problems may force abandonment of a well. In addition, delays in controlling lost circulation can lead to highly complex problems, including the failure to control the lost circulation in any meaningful way.
Lost circulation can be categorized as seepage type, moderate type, severe type, and total loss, referring to the amount of fluid or mud lost. The extent of the fluid loss and the ability to control the lost circulation with an LCM depends on the type of formation in which the lost circulation occurs. Formations with low permeability zones, that is, those with microscopic cracks and fissures, usually have seepage type lost circulation. Other formations may experience lost circulation if an improper mud weight is used while drilling. Such formations include narrow mud weight window, low fracture gradient, depleted reservoir pressure, formations with soluble minerals such as halite, evaporate, and anhydrite.